Difference between revisions of "AVG"

From SQLZOO
Jump to: navigation, search
(Created page with "<table align='right' border='1'> <caption>Compatibility</caption> <tr><th colspan='3'>AVG(f)</th></tr> <tr><td align='center'>'''Engine'''</td><td align='center'>'''OK'''</td>...")
 
Line 9: Line 9:
 
<tr><td align='left'>sqlserver</td><td>Yes</td><td></td></tr>
 
<tr><td align='left'>sqlserver</td><td>Yes</td><td></td></tr>
 
</table>
 
</table>
<h3>AVG</h3>
+
<h1>AVG</h1>
 
<p>AVG gives the average (the mean) of a whole column or a group of rows for a single column of values.</p>
 
<p>AVG gives the average (the mean) of a whole column or a group of rows for a single column of values.</p>
 
<p>AVG is an aggregate function it is normally used with GROUP BY.</p>
 
<p>AVG is an aggregate function it is normally used with GROUP BY.</p>
Line 32: Line 32:
 
<ul>
 
<ul>
 
   <li>[http://sqlzoo.net/w/index.php/MAX MAX function]</li>
 
   <li>[http://sqlzoo.net/w/index.php/MAX MAX function]</li>
   <li>[[COUNT function]]</li>
+
   <li>[http://sqlzoo.net/w/index.php/COUNT COUNT function]</li>
 
   <li>[http://sqlzoo.net/w/index.php/MIN MIN function]</li>
 
   <li>[http://sqlzoo.net/w/index.php/MIN MIN function]</li>
 
</ul>
 
</ul>

Revision as of 10:53, 13 July 2012

Compatibility
AVG(f)
EngineOKAlternative
ingresYes
mysqlYes
oracleYes
postgresYes
sqlserverYes

AVG

AVG gives the average (the mean) of a whole column or a group of rows for a single column of values.

AVG is an aggregate function it is normally used with GROUP BY.

The mean of the values 2, 5, 5 is (2+5+5)/3 = 12/3 = 4, you divide by 3 because there are 3 numbers in this example.

NULL values do not contribute to the calculation.

    SELECT region, AVG(population)
    FROM bbc
   GROUP BY region 

With a GROUP BY region statement each region shows up just once. The AVG column gives the average population per country for each region.

SELECT region, AVG(population)
  FROM bbc
 GROUP BY region

See also

Personal tools
Namespaces

Variants
Actions
Reference
Toolbox
Google AdSense